On Oct 13, 12:56*pm, "Phil Kangas" wrote:
..
So what I'm reading is the information given on this gauge
is pretty much a
waste of time. Why give double depth of thread when the
compound
rest only affects the radius. It would be far more handy if
that chart
gave the actual compound rest movement required for a given
thread.
And the four most common threads (14, 20, 24, 32) ? Thread
pitch
gauges are far more useful than the scales given. My
curiosity has been
satisfied.
phil

When you cut an ending groove with a different tool and dial readings,
it's deep enough when your calipers read (OD - DoubleDepth). If I have
several threads to do I'll leave the dials zeroed for threading and
cut the grooves by measurement. A groove that's slightly too deep is
far less important than getting the threads right.

The actual compound movement varies with the tip width if you measure
in from initial contact. If you ground a sharp point you'd have to cut
in the full Sharp Vee depth to get the pitch diameter correct. As I
mentioned, the two numbers I found useful are the double depth they
gave and the compound feed which is specific to the way I personally
cut threads.

Those four pitch rulers work for fractional and multiple pitches as
well. You can check 7, 10, 12, 14, 16, 20, 24, 28, and 32.

Jim Wilkins